Detect DCs without fonts and return an error in wglUseBitmapFonts.

dlls/opengl32/wgl.c

@@ -445,7 +445,7 @@ BOOL WINAPI wglSwapLayerBuffers(HDC hdc,
   if (fuPlanes) {
     WARN("Following layers unhandled : %08x\n", fuPlanes);
   }
-  
+
   return TRUE;
 }
 
@@ -459,7 +459,9 @@ BOOL WINAPI wglUseFontBitmapsA(HDC hdc,
 {
   Font fid = get_font( hdc );
 
-  TRACE("(%08x, %ld, %ld, %ld)\n", hdc, first, count, listBase);
+  TRACE("(%08x, %ld, %ld, %ld) using font %ld\n", hdc, first, count, listBase, fid);
+
+  if (fid == 0) return FALSE;
 
   ENTER_GL();
   /* I assume that the glyphs are at the same position for X and for Windows */

graphics/x11drv/init.c

@@ -290,6 +290,7 @@ INT X11DRV_ExtEscape( X11DRV_PDEVICE *physDev, INT escape, INT in_count, LPCVOID
                 if (out_count >= sizeof(Font))
                 {
                     fontObject* pfo = XFONT_GetFontObject( physDev->font );
+		    if (pfo == NULL) return FALSE;
                     *(Font *)out_data = pfo->fs->fid;
                     return TRUE;
                 }